**Stimulus Photography and matching procedure** Photographs were collected using the procedure outlined in [osf.io/3f6hn][1]. However, the stimulus preparations differ slightly, as in the current study the 3D images are static and the faces are shown from three different angles; the front, left portrait and right portrait. An example of [this][2] **Stimulus preparation** There are three versions of the stimuli set. - One version with no alterations [(individual shape and individual colour retained)][2] - One in which the individual shape had been removed [(individual colour retained)][3] The shape of all faces was the average shape of the set. - One in which the individual colour had been removed [(individual shape retained)][4] **Stimulus matching procedure** From a set of images of individuals of varying ages, sex and relatedness, we algorithmically chose the maximum number of sibling pairs where both siblings were under the age of 18, and an age-matched (within 1 year), ethnicity-matched, and sex-matched foil image was available from family units that were not represented elsewhere in the image set. Specifically, the two individuals in each sibling pair are related to each other, but not to any other individual in the set, while all individuals in unrelated pairs are related to no individuals in the set. All individuals in the set gave verbal assent and their parent or guardian gave written consent for their images to be used in scientific research. Attached is the [data file][5] with information about the sibling and foil pairs. [1]: https://osf.io/3f6hn [2]: https://osf.io/ynz82 [3]: https://osf.io/hxkct [4]: https://osf.io/472fr [5]: https://osf.io/5qgs6/